This Program-Project in Liver Diseases represents the outgrowth of a series of interactions of medical scientists at this institution which has developed over a number of years, and which has evolved naturally from overlapping interests in various aspects of liver physiology, biochemistry and disease. The merging of approaches of various disciplines is intertwined in a series of major projects concerned with: 1) the etiology, pathogenesis and treatment of viral hepatitis and of liver disease, both acute and chronic encountered in a high proportion of our renal transplant patients; 2) the potential genetic basis for postulated immunologic abnormalities that contribute to the development of chronic liver disease, using the chronic hepatitis B carrier as the initial focal point for assessment; 3) the mechanisms involved in drug-induced liver injury; 4) regulation of intermediary metabolism in liver, utilizing isolated liver cell preparations as an important experimental tool; 5) hepatic transport function, with major emphasis concerned with sinusoidal uptake processes and canalicular excretory mechanisms; and 6) sex hormone metabolism in patients with chronic liver disease and in alcoholics without liver disease.